LATE TERTIARY ORIGINS OF THE ARCTIC BEETLE FAUNA

Abstract

During the past 30years, Quaternary insect paleontologists working in the Arctic have studied rare deposits of fossil insects that date back millions of years. Some of these fossils may be as old as the Late Miocene. The fossils have been preserved mostly in permafrost environments, and their state of preservation is often exceptional. The vast majority of identifiable beetle specimens appear to match modern, extant species. This morphological constancy through time appears to reflect constancy of physiological adaptations, as well. The latter aspect is demonstrated indirectly through the ecological compatibility of species found in the ancient fossil assemblages. While most of the species themselves appear to have remained constant, the biological communities in which they lived have shifted dramatically through time. Based on both insect and plant fossil data, Late Tertiary environments of the Arctic were substantially warmer than they are today, supporting the growth of coniferous forests, up to the shores of the ancient Arctic Ocean. By about 2million years ago (my) or shortly thereafter, Arctic tundra communities came into existence in parts of Beringia. Arctic insect faunal diversity declined markedly with the onset of Quaternary cooling.